If I flew a Legacy, I might consider the following until a best practice is agreed upon:
I would use something like several feet of a swim noodle to hold the canopy open and would always secure such when the noodle was removed.  I know that I could miss a check list item, warning light, etc. but I doubt that I would miss a foam tube along the side of my head along with takeoff prop wash.  The "either - or" option of having the canopy open or locked would work for me.
Greg Milnar